4. Skull (Wright) Flashcards
What make up our axial skeleton?
- 1. Skull
- 2. Vertebral column
- 3. Thoracic cage
What makes up our appendicular skeleton?
1. Upper and lower limbs
2. Pectoral/pelvic girdles
What are the 8 cranial bones?
- Parietal (2 because paired)
- Temporal (2 because paired)
- Frontal
- Occipital
- Sphenoid
- Ethmoid
What are the 14 facial bones?
- Zygomatic (2 because paired)
- Lacrimal (2 because paired)
- Nasal (2 because paired)
- Palatine (2 because paired)
- Maxillae (2 because paired)
- Inferior nasal conchae (2 because paired)
- Vomer
- Mandible
Craniometric landmarks
- Pterion
- Lambda
- Glabella
- Nasion
- Akanthion
- Inion
- Pogonion
- Pterion-> where frontal, parietal, temporal and sphenoid bone meet. Middle meningeal A runs through it.
- Lambda-> intersection of sagittal and lamboid sutures and location of posterior fontanelle.
- Glabella -> area superior to nasion between supraorbital tori/
- Nasion -> intersection of two nasal bones and frontal
- Akanthion-> where nasal prominence comes out
- Inion-> occipital protuberance
- Pogonion- tip of chin
Damage to the pterion can damage what?
Middle meningeal A.
We lacked ______ in primitive species. However, they since have appeared and enlarged during skull evolution.
Fenestrae - holes that open and connect with the orbit of the eye.
How has neurocranium evolved over time? (?)
Maintained fetal form of skull in adulthood
Where does the frontal bone meet the parietal bone?
Coronal suture
Bulging over eyes on exterior skull is called
superciliary arch
What is a midline remnant of the fused frontal bones?
can result in?
Metopic sutures; can result in cleft lip
What part of skill do you get the terminal branching of V1 (supraorbital N) arising and vessels, which provides sensation to the skin on the forehead?
Supraorbital notch/foramen
What is the frontal crest?
Attachment site for falx cerebri, which is protective connective tissue for the brain.
Located: internal surface of frontal bone.
PARIETAL BONE
What is the articulation between the two parietal bones?
Sagittal sutures
Where occipital bone meets parietal bone
Lambdoidal Suture
Where parietal bone meets temporal bone
Squamosal suture
CN: surgical access to cranial cavity: bone flaps
how can we improve healing?
Surgeons access the cranial cavity and brain by performing a craniotomy, where a section of the neurocranium, called a bone flap, is elevated or removed. Bone flaps are put back into place with wire or metal plates.
Healing is best when flap has overlaying muscle and skin, so that it retains its own blood supply during the procedure and after repositioning.
If the bone flap is not replaced (i.e., a permanent plastic or metal plate replaces the flap), the procedure is called a
cranioectomy
How can we age bones?
- By looking at sutures.
- As we age, lines fuse and obliterate.
- Beginning at 30-40 years old-> internal surface obliterate
- 10 years later-> external surgace obliterates
Obliteration of sutures usually begins at the _____ and continues sequentially in the _____, _____, and _____ sutures. Closure times vary considerably.
Obliteration of sutures usually begins at the bregma and continues sequentially in the sagittal, coronal, and lambdoid sutures. Closure times vary considerably.
What houses the middle ear and is important for hearing and balance and CNS?
TEMPORAL BONE
Houses facial N and branches.
Important things on external surface of temporal bone
- Zygomatic process
- Mastoid process
- Styloid process
- Mandibular fossa
- External auditory meatus
Important things on interior surface of temporal bone
- Groove for sigmoid venous sinus
- Internal acoustic meatus-> CN 7 and 8 run through it.
- Petrous portion- hard part of temporal bone that protects inner ear
What is a passageway for
1. medulla oblongata
2. accessory nerve
3. vertebral as.
Foramen magnum
___________ enters the foramen magnum and exits the jugular foramen.
Spinal accessory n.
Where does C1 articulate with skull?
Occipital condyles
What are attachment sites for muscles of the back and neck?
1. Inferior nuchal line
2. Superior nuchal line
When nodding yes, what happens?
Occipital condyles meet with cervical vertebrae (atlas of C1)
Hypoglossal Canal
Located:
Conveys:
Located: superior and anterior to occipital condyles
Conveys: Hypoglossal nerve
Jugular Notch
Internal jugular V runs in notch.
What is the venous drainage for the brain?
Venous drainage of the brain is located on the internal surface of occipital bone and makes a S.
- Groove for superior sagittal sinus
- Groove for transverse sinus
- Groove for sigmoid sinus
- > jugular notch (internal jugular vein)
Superior part of spenoid bone looks like:
batman
Where does the pituitary gland sit?
Sella turcica of the sphenoid bone
Optic canal
Conveys:
- Optic nerve
- Opthalmic a.
Foramen Rotundum
Location:
Conveyed:
Location: junction of the [anterior and medial parts] of the sphenoid bone
Conveyed: exit point for maxillary branch of trigeminal nerve (V2)
Foramen Ovale
Conveys:
Exit point for mandibular branch of the trigeminal nerve (V3)
Foramen Spinosum
Conveys:
Exit point for middle meningeal A.
Superior Orbital Fissure
Conveys:
- Trochlear nerve,
- Frontal nerve
- Lacrimal nerve,
- Abducens nerve
- Oculomotor nerve,
- Superior Ophthalmic veins
Pterygoid or Vidian Canal
Located at the anterior end of the _________ at the base of the pterygoid plates. It is best seen from a basal view. Anteriorly, it enters the _______________.
Pterygoid (Vidian) Canal is located at the anterior end of the carotid canal at the base of the pterygoid plates. It is best seen from a basal view. Anteriorly, it enters the sphenopalatine fossa
What runs in Pterygoid (Vidian) canal?
Pterygoid (Vidian) nerve and vessels
______ units the cranial and facial bones
sphenoid
what does the sphenoid bone articulate with?
almost every bone in the skull
The sphenoid bone has _______, located deep to the body of the sphenoid and infections can occur here.
Sphenoid sinuses
Things on ethmoid bone:
- Crista galli
- Orbital plate
- Perpendicular plate
- Ethmoidal labyrinth
- Crista galli -> attachment for falx cerebri
- Orbital plate-> forms medial wall of the orbit
- Perpendicular plate -> superior portion of nasal septum
- Ethmoidal labyrinth -> made up of superior and middle nasal conchae
Cribiform plate
on ethmoid bone
Olfactory nerve descends along lateral borders.
Cribiform foramina
Conveys:
- Olfactory nerves (and branches)
- Nasociliary nerves
- Anterior Ethmoidal nerves
3 cranial fossae
1. Anterior cranial fossae
2. Middle cranial fossae
3. Posterior cranial fossae
What is the fx of facial bones?
- Provide shape, contour and individuality
- Important component for orbit and nasal cavities
- Anchor site for teeth of upper and lower jaw
What makes up our zygomatic arch?
- Zygomatic process of temporal bone
- Temporal process of zygomatic bone
What is the lacrimal bone?
Part of medial wall of each orbit
What is the nasal bone?
Paired bones that form bridge of nose
lacrimal groove
Opening for nasolacrimal duct
Vomer bone
2 parts:
- Ala- articulates with sphenoid bone
- Vertical plate- forms the inferior portion of nasal septum
Palatine bone: 3 parts
- Orbital process- forms medial floor of orbit
- Perpendicular plate- lateral wall of nasal cavity
- Horizontal plate- posterior portion of hard palate
how can we get cleft lip and cleft palate
Cleft lip: Nonfusion of hard palate
If the cleft palate extenfs through the alveolar processes of maxilla and lips on both sides -> cleft palate.
Maxilla bone
- Palatine process
- Incisive foramen
- Alveolar process
- Maxillary sinus
- Palatine process -> posterior portion of hard palate
- Incisive foramen -> seperates hard palate from anterior nasal spine; nasopalatine nerve runs through
- Alveolar process -> hold teeth of upper jaw
- Maxillary sinus -> largest paranasal sinus in skull
Infraorbital Foramen or Notch
Located:
Conveys:
on maxilla bone.
Converys: Infraorbital artery and nerve
Le Fort fractures
Le Fort I fracture: wide variety of horizontal fractures of the maxillae, passing superior to the maxillary alveo- lar process (i.e., to the roots of the teeth), crossing the bony nasal septum and possibly the pterygoid plates of the sphenoid.
Le Fort II fracture: passes from the posterolateral parts of the maxillary sinuses (cavities in the maxillae) supero- medially through the infra-orbital foramina, lacrimals, or ethmoids to the bridge of the nose. As a result, the entire central part of the face, including the hard palate and alve- olar processes, is separated from the rest of the cranium.
• Le Fort III fracture: horizontal fracture that passes through the superior orbital fissures and the ethmoid and nasal bones and extends laterally through the greater wings of the sphenoid and the frontozygomatic sutures. Concurrent fracturing of the zygomatic arches causes the maxillae and zygomatic bones to separate from the rest of the cranium.
A broken mandible usually involves _____ fractures.
two
- Fractures of the _____________ are uncommon and usually single.
- Fractures of the ____________ are often transverse and may be associated with dislocation of TMJ (temporomandibular joint).
Fractures of the coronoid process of the mandible are uncommon and usually single.
Fractures of the neck of the mandible are often transverse and may be assx with dislocation of TMJ.
What SIX bones make up nasal complex?
- Nasal bone
- Lacrimal bone
- Sphenoid bone
- Maxilla bone
- Horizontal plate of palatine bone
- Inferior nasal concha
Is inferior nasal concha part. of ethmoid bone?
No. It. is its own seperate bone.
Superior and middle concha are. part of ethmoid bone.
What SEVEN bones make up the orbital complex?
Lateral wall (3)
- Zygomatic process of frontal bone
- Greater wing of sphenoid bone
- Orbital surface of zygomatic bone
Medial wall (3)
- Frontal process of maxilla bone
- Lacrimal bone
- Lateral mass of ethmoid bone
Floor of orbit (3)
- Perpendicular plate of palatine bone
- orbital surface of maxilla
- Zygomatic bone
Roof of orbit (2)
- Lesser wing of spenoid bone
- Frontal bone
4 paranasal sinuses
- Frontal sinus
- Sphenoid sinuses
- Ethmoid sinuses
- maxillar sinuses
Fetal skull has fontanelles. What are their purpose?
The softness of the cranial bones in fetuses and their loose connections at the sutures and fontanelles enable the shape of the cranium to be molded during birth.
4 fetal fontanelle
- anterior fontanelle
- Sphenoid fontanelle
- Mastiod fontanelle
- posterior fontanelle
what. is the largest fontanelle where. you. can extract CSF?
Anterior fontanelle
